Memory loss due to normal aging is usually not a cause for concern, if it does not interfere with work, home and social life. A mental health disorder, such as stress, anxiety or depression can cause confusion, forgetfulness and lack of focus, states Mayo Clinic. Bipolar disorder, schizophrenia and dementia are additional mental health problems that cause memory loss, states MedlinePlus.

Individuals that consume excessive alcohol, especially those that have alcoholism or mix alcohol with other drugs or medication, suffer from memory loss due to the impairment of mental capabilities, notes Mayo Clinic. Brain tumors, concussions and stroke are types of brain injuries that cause memory loss. Chemotherapy and bone-marrow transplants are some cancer treatments that cause memory loss, states MedlinePlus.